scholarly journals Characterization and application of FRCM as a strengthening material for shear-critical RC beams

2018 ◽  
Vol 199 ◽  
pp. 09004
Author(s):  
Adel Younis ◽  
Usama Ebead
Keyword(s):  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Shear Strengthening ◽  
Structural Capacity ◽  
Test Parameters ◽  
Study Results ◽  
Glass Carbon ◽  
Characterization Test ◽  
Fabric Reinforced Cementitious Matrix

This paper investigates the effectiveness of fabric reinforced cementitious matrix (FRCM) systems in shear-strengthening of reinforced concrete beams. Three types of FRCM systems were considered, namely, polyparaphenylene benzobisoxazole (PBO)-FRCM, Carbon-FRCM, and Glass-FRCM. At first, tensile characterization test was performed on 15 FRCM coupons with the aim of identifying the tensile properties of the FRCM systems adopted. After that, seven shear-critical RC beams were tested under three-point loading, with the consideration of two test parameters: (a) FRCM material (glass/carbon/PBO); and (b) strengthening configuration (full/intermittent). The study results revealed the use of FRCM as a strengthening material to achieve a considerable improvement in the structural capacity of shear-critical RC beams. The average gain in the shear capacity of the FRCM-strengthened beams was 57%. The beam specimens strengthened with carbon-FRCM showed the highest improvement as compared to those strengthened with glass-and PBO-FRCM systems. As intuitively expected, the shear capacity improvement achieved with the full-length strengthening systems was generally higher than that with the intermittent counterparts.

scholarly journals Applications of bolted steel plates to shear strengthening of RC beams

2019 ◽  
Vol 276 ◽  
pp. 01002
Author(s):  
I Ketut Sudarsana ◽  
I Putu Chandra Sajana ◽  
I Gusti Ngurah Oka Suputra
Keyword(s):  
Steel Plate ◽  
Concrete Strength ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Steel Plates ◽  
Beam Deflection ◽  
Rc Beams ◽  
Shear Strengthening ◽  
External Reinforcement ◽  
Beam Shear

Many reinforced concrete beams have been found deficiencies in shear due to lack of shear reinforcement. Few researches have been done to investigate shear strengthening of low concrete strength of RC beams using bolted steel plates. This paper presents experimental results on the behaviour of RC beams strengthening using full steel plates along the shear span fixed with bolts. Nine RC beams having dimension of 150x200x1500mm were tested to failure on simply supports with four point loadings setup. The beams were reinforced with tension rebars area of 289.8 mm2 (2D10+1D13) and transvers reinforcement of Ø6-125. Two dial gauges were installed at the beam middle span to measure beam deflection during the test. The results show that the applications of steel plate and bolts as external reinforcement increase beam shear capacity, stiffness and delay the occurrence of first diagonal cracks. Beams stregnthened with U-shape plates gave better performances than the beams with two pieces of L-shape plates due to better achorages.

AN EFFECTIVE TECHNIQUE UTILIZING FRCM SYSTEM IN STRENGTHENING RC BEAMS IN SHEAR

2018 ◽  
Vol 5 (1) ◽  
Author(s):  
Tadesse Wakjira ◽  
Usama Ebead
Keyword(s):  
Concrete Cover ◽  
Shear Capacity ◽  
Rc Beams ◽  
Test Results ◽  
Effective Technique ◽  
Near Surface ◽  
Test Parameters ◽  
Different Types ◽  
A New Technique ◽  
Fabric Reinforced Cementitious Matrix

This paper presents the efficacy of a new technique of fabric reinforced cementitious matrix (FRCM) for the strengthening of shear deficient reinforced concrete (RC) beams. This technique involves embedding the FRCM composites in the concrete cover and is referred to as “near surface embedded” FRCM (NSE-FRCM) technique. Five (5) medium scale rectangular RC beams of width × depth × length of 150 × 330 × 2100 mm were constructed and tested under displacement controlled with three-point loading. One beam was kept unstrengthen as a control specimen whereas the other four beams were strengthened with different types and configurations of the NSE-FRCM system. The test parameters were: (a) geometric configuration (intermittent strips of NSE-FRCM versus full NSE-FRCM plate), and (b) fabric types (carbon versus glass fabrics). The test results indicated that the NSE-FRCM technique can successfully be used to significantly enhance the shear capacity of the strengthened beams. The strengthened specimens exhibited an average enhancement in the shear capacity of 62% over the unstrengthen beam. The full NSE-FRCM plate showed higher enhancement in the shear strength compared to that for the intermittent NSE-FRCM configuration. Moreover, the specimens strengthened with carbon FRCM showed higher shear capacity compared to that with glass FRCM counterparts.

Predicting the effect of stirrups on shear strength of reinforced normal-strength concrete (NSC) and high-strength concrete (HSC) slender beams using artificial intelligence

2006 ◽  
Vol 33 (8) ◽  
pp. 933-944 ◽  
Author(s):  
H El Chabib ◽  
M Nehdi ◽  
A Saïd
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
High Strength ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Design Parameters ◽  
Rc Beams ◽  
Shear Reinforcement ◽  
Strength Concrete ◽  
Shear Design

The exact effect that each of the basic shear design parameters exerts on the shear capacity of reinforced concrete (RC) beams without shear reinforcement (Vc) is still unclear. Previous research on this subject often yielded contradictory results, especially for reinforced high-strength concrete (HSC) beams. Furthermore, by simply adding Vc and the contribution of stirrups Vs to calculate the ultimate shear capacity Vu, current shear design practice assumes that the addition of stirrups does not alter the effect of shear design parameters on Vc. This paper investigates the validity of such a practice. Data on 656 reinforced concrete beams were used to train an artificial neural network model to predict the shear capacity of reinforced concrete beams and evaluate the performance of several existing shear strength calculation procedures. A parametric study revealed that the effect of shear reinforcement on the shear strength of RC beams decreases at a higher reinforcement ratio. It was also observed that the concrete contribution to shear resistance, Vc, in RC beams with shear reinforcement is noticeably larger than that in beams without shear reinforcement, and therefore most current shear design procedures provide conservative predictions for the shear strength of RC beams with shear reinforcement.Key words: analysis, artificial intelligence, beam depth, compressive strength, modeling, shear span, shear strength.

scholarly journals Shear Strengthening Performance of Hybrid FRP-FRCM

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Kyusan Jung ◽  
Kinam Hong ◽  
Sanghoon Han ◽  
Jaekyu Park ◽  
Jaehyun Kim
Keyword(s):  
Shear Capacity ◽  
Shear Strengthening ◽  
Cementitious Matrix ◽  
Reinforced Polymer ◽  
Capacity Model ◽  
Proposed Model ◽  
Externally Bonded ◽  
Strengthened Beam ◽  
Fabric Reinforced Cementitious Matrix ◽  
Glass Frp

The effectiveness of a hybrid fiber reinforced polymer- (FRP-) fabric reinforced cementitious matrix (FRCM) for shear strengthening was investigated though an experimental study. FRP materials of FRCM are usually fabricated in the form of a fabric to enhance the bond strength between the FRP material and the cementitious matrix. The hybrid FRP fabric used in this study consisted of carbon FRP (CFRP) and glass FRP (GFRP) in warp and weft directions, respectively. A total of 11 beams were fabricated and 8 beams among them were strengthened in shear with externally bonded hybrid FRP-FRCM. The number of plies, the bond types, and the spacing of the hybrid FRP fabric were considered as experimental variables. Additionally, a shear capacity model for a FRCM shear strengthened beam was proposed. The values predicted by the proposed model were compared with those by the ACI 549 code and test results. It was confirmed from the comparison that the proposed model predicted the shear strengthening performance of the hybrid FRP-FRCM more reliably than the ACI 549 code did.

scholarly journals Combined Flexural and Shear Strengthening of RC T-Beams with FRP and TRM: Experimental Study and Parametric Finite Element Analyses

Buildings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 520
Author(s):  
Daniel A. Pohoryles ◽  
Jose Melo ◽  
Tiziana Rossetto
Keyword(s):  
Experimental Study ◽  
Finite Element ◽  
Shear Capacity ◽  
Fe Model ◽  
Rc Beams ◽  
Shear Strengthening ◽  
Flexural Strengthening ◽  
Existing Structures ◽  
The Difference ◽  
Reinforcement Design

Due to inadequacies of reinforcement design in older structures and changes in building codes, but also the change of building use in existing structures, reinforced concrete (RC) beams often require upgrading during building renovation. The combined shear and flexural strengthening with composite materials, fibre-reinforced polymer sheets (FRP) and textile reinforced mortars (TRM), is assessed in this study. An experimental campaign on twelve half-scale retrofitted RC beams is presented, looking at various parameters of interest, including the effect of the steel reinforcement ratio on the retrofit effectiveness, the amount of composite material used for strengthening and the effect of the shear span, as well as the difference in effectiveness of FRP and TRM in strengthening RC beams. Significant effects on the shear capacity of composite retrofitted beams are observed for all studied parameters. The experimental study is used as a basis for developing a detailed finite element (FE) model for RC beams strengthened with FRP. The results of the FE model are compared to the experimental results and used to design a parametric study to further study the effect of the investigated parameters on the retrofit effectiveness.

Numerical Analysis for Reinforced Concrete Beams with Circular Openings in Flexural and Shear Zones Strengthened by Steel Plates

2018 ◽  
Vol 23 (2) ◽  
pp. 31-48
Author(s):  
Ahmed Ali AL-Dhabyani ◽  
Abdulwahab AL-Ansi
Keyword(s):  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Ultimate Load ◽  
Shear Zones ◽  
Reinforced Concrete Beams ◽  
Steel Plates ◽  
Load Carrying Capacity ◽  
Rc Beams ◽  
Study Results ◽  
Load Carrying

In the modern building construction, openings in beams are necessary to accommodate several service pipes and ducts. Due to these openings, high stress concentration occurs at its edges. Local cracks also appear around the openings as a result of the reduction in the beam stiffness, the load carrying capacity and the shear capacity. There are many studies which were conducted to develop and test different strengthening methods for the beams opining to increase the ultimate load capacity of the beams. However, from a practical point of view, it is better to have one strengthening method having the same specifications to be used in both; shear and flexural zones for circular opining beams in buildings. In spite of the prior studies, no study has addressed this issue; therefore, there is a need to study such a case. In this paper, an analytical study was conducted to investigate the behavior of the reinforced concrete (RC) beams with circular openings in flexural and shear zones strengthened by steel plates. A 3D FE modeling (ABAQUS 6.12) software was used to simulate five different specimens of RC beams. The study results showed that when the openings were strengthened by steel plates, the ultimate load carrying capacity increased, but the deflection was decreased when compared to the openings without strengthening. In addition, the model reliability was verified via good agreements between the experimental and numerical results.

BOND AND SHEAR-STRENGTHENING PERFORMANCE OF FRCM COMPOSITES

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Adel Younis ◽  
Usama Ebead
Keyword(s):  
Rc Beam ◽  
Load Carrying Capacity ◽  
Rc Beams ◽  
Test Results ◽  
Shear Strengthening ◽  
Double Shear ◽  
Structural Improvement ◽  
Load Carrying ◽  
Double Shear Test ◽  
Fabric Reinforced Cementitious Matrix

This paper is aimed at studying the bond and shear-strengthening performance of fabric reinforced cementitious matrix (FRCM) systems. Three FRCM systems were compared, namely, polyparaphenylene benzobisoxazole (PBO)-FRCM, Carbon-FRCM, and Glass-FRCM. At first, six double-shear specimens were tested to investigate the FRCM/concrete bond, with the test variables including the fabric type and the bond length. After that, seven shear-critical reinforced concrete (RC) beams were tested under three-point loading, considering the fabric type and strengthening configuration (full/intermittent) as the test variables. As for the double-shear test results, the failure observed was fabric/matrix debonding in carbon-FRCM, matrix/concrete debonding in PBO-FRCM, and fabric rapture in glass-FRCM. The FRCM/concrete bond increased with the bonded length, and the PBO-FRCM showed the highest bond to concrete. Regarding the RC beam tests, the FRCM-strengthened beams showed the same failure mode that is debonding at the FRCM/concrete interface. Nonetheless, FRCM had successfully strengthened the beams in shear: an average gain of 57% in the load carrying capacity was achieved as compared to the non-strengthened reference. Indeed, the full-length strengthening resulted in a better structural improvement compared to the intermittent-strengthening configuration. Amongst the three systems, carbon-FRCM systems were the most efficient in shear-strengthening RC beams.

FRCM SHEAR STRENGTHENING FOR CONCRETE BEAMS

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Adel Younis ◽  
Usama Ebead ◽  
Kshitij C. Shrestha
Keyword(s):  
Shear Zone ◽  
Carbon Fibers ◽  
Shear Failure ◽  
Load Capacity ◽  
Full Length ◽  
Rc Beams ◽  
Test Results ◽  
Shear Strengthening ◽  
Strength Enhancement ◽  
Fabric Reinforced Cementitious Matrix

This paper presents the results of an experimental study carried out to examine the efficacy of Fabric-Reinforced Cementitious Matrix (FRCM) in strengthening RC beams susceptible to shear failure. In this paper, seven shear-critical RC beams, of 2,500 mm in length, 150 mm in width, and 330 mm in depth, were tested under three-point loading until failure. Two main test variables were considered, which are: a) Strengthening material: carbon, polyparaphenylene benzobisoxazole (PBO), or glass FRCM, and b) Strengthening application pattern: a single full-length FRCM plate or a set of intermittent and spaced FRCM strips were applied along the critical shear zone. The test results confirmed the efficacy of FRCM strengthening in improving the load capacity of shear-critical RC beams. The FRCM-strengthening contributed to increases in the load capacity ranged between 31% and 100% compared to the reference specimen. The full-length strengthened specimens generally showed a better strength enhancement compared to the intermittent counterparts when using the same FRCM material. Such intuitive observation assures the importance of the amount of strengthening material applied in the critical shear zone. Besides, specimens utilizing carbon fibers in its FRCM strengthening material showed the highest strength enhancement among the three systems.

Calculation of Shear Capacity of Steel Reinforced Concrete Beams Strengthened with Near-Surface Mounted CFRP Rods

2012 ◽  
Vol 193-194 ◽  
pp. 852-854
Author(s):  
Wei Hua Chen ◽  
Mei Qin Wu
Keyword(s):  
Reinforced Concrete ◽  
Reinforced Concrete Beam ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Near Surface ◽  
Steel Reinforced Concrete ◽  
Carbon Fiber Reinforce Polymer ◽  
Near Surface Mounted ◽  
Fiber Reinforce

Some calculated methods of shear capacity of RC beams strengthened with NSM(near-surface mounted) CFRP(Carbon fiber reinforce polymer) rods are reviewed based on the experimental data on shear capacity of RC beams strengthened with NSM CFRP rods. Therefore, according to the destruction forms of steel reinforced concrete beam strengthened with NSM CFRP rods, the formula for calculating the shear capacity of the beam is given. The formula is expressed clearly, simple and easy to use.

Test Study on the Resisting Shear Strengthening Effect with External Pre-Stressed Wire Rope

2011 ◽  
Vol 243-249 ◽  
pp. 5571-5575 ◽  
Author(s):  
Tian Lai Yu ◽  
Qiang Ma ◽  
Lei Lei Tian
Keyword(s):  
Reinforced Concrete ◽  
Strengthening Mechanism ◽  
Wire Rope ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Design Parameters ◽  
Strengthening Effect ◽  
Shear Strengthening ◽  
Research Results ◽  
Beam Design

The resisting shear strengthening technology of existing reinforced concrete bridges as an important research topic in the field of old bridges, play an important significance to improve the mechanical properties of old bridges and reduce security incidents. Based on comparative test analysis on two basic beams and twelve reinforced concrete beams strengthened with external pre-stressed wire rope, the influence of the shear strengthening effect was studied systematically caused by the original beam design parameters and the spacing of wire rope, in the meantime the strengthening mechanism was analyzed. Research results showed that the shear capacity of the strengthened beams was improved, because the development of cracks was not only effectively limited, but also stirrup strain was reduced, and yield load was put off. Along with the increasing of the ratio of original beams longitudinal reinforcement and the ratio of stirrup ,and the concrete grade, as well as the decreasing of spacing of external wire rope, the stirrups strain were decreasing and the shear capacity of strengthened beams increased. With the spacing of external wire rope decreasing, the diagonal crack resistance of the strengthened beams increased. The research results can provide reference for the design and research on shear strengthening of bridges.

Sign in / Sign up

Export Citation Format

Share Document